Insect cells such as SF21 and SF9 cells are commonly used for protein expression, including for the production of therapeutic biological products for use in human disease. Insect cells are often used in conjunction with baculovirus expression systems. Such baculovirus-insect cell expression systems have been used for the production of biological products due to their ability to grow to high density and express sufficient levels of protein, and due to the fact that they can readily be adapted to large scale suspension cultures. It has long been thought that these cells are free of contaminating viruses, as a result of extensive testing.
There is a need in the art for insect cells that are free of contaminating viruses, for methods for determining if the insect cells are free of contaminating viruses, and for products produced from insect cells that are free of contaminating viruses and suitable for human therapies.